As a main component of an antenna, a phase shifter can adjust a downtilt of an antenna beam by changing phase distribution of all radiating elements of the antenna, so as to improve network coverage and facilitate network optimization.
With development of mobile communications technologies, multi-band and multi-mode communication is also evolving, and a multi-band antenna that supports multi-band and multi-mode communication emerges. The multi-band antenna may include multiple phase shifters, and each phase shifter may be connected to multiple radiating elements. Each phase shifter may adjust, in phases of the multiple radiating elements connected to each phase shifter, an electromagnetic wave signal of a band corresponding to each phase shifter, to implement frequency division on the electromagnetic wave signal of the band in the multiple radiating elements, and emit the electromagnetic wave signal by using each of the multiple radiating elements connected to each phase shifter. Each phase shifter may be connected to a radio remote unit (RRU for short) of a base station by using a cable, so as to receive an electromagnetic wave signal that is of a band corresponding to each phase shifter and sent by the RRU. That is, the multiple phase shifters of the multi-band antenna may be connected to the RRU by using multiple cables.
However, there are a relatively large quantity of cables for connecting the antenna to the RRU. Consequently, a connection error easily occurs, causing the phase shifter to receive an electromagnetic wave signal of an incorrect band, and leading to an error in transmitting a signal by the antenna.